In heavy trucks with dual fuel tanks, the tanks are usually mounted on opposite sides of the frame, and the bottoms of the two tanks are connected by a crossover fuel equalization line. The crossover line must extend between the two tanks along the underside of the vehicle at its lowest point. Thus, the crossover line is vulnerable to being torn from the truck by road obstructions during normal use or in an accident. The tearing or breaking of the crossover line allows fuel to be spilled and thereby results in fuel loss and fire and other hazards.
Coupling joints with automatic sealing of both ends when the joint is separated are disclosed in U.S. Pat. Nos. 2,614,866, granted Oct. 21, 1952, to R. M. Ulrich; 3,026,070, granted Mar. 20, 1962, to R. W. Sutton et al.; 3,035,797, granted May 22, 1962, to R. Neuschotz; 3,043,542, granted July 10, 1962, to R. Neuschotz; 3,112,767, granted Dec. 3, 1963, to E. J. Cator; 3,312,431, granted Apr. 4, 1967, to C. L. Vogt; 3,482,602, granted Dec. 9, 1969, to M. Jarnagan et al.; 3,490,491, granted Jan. 20, 1970, to L. A. Kopaska; 3,599,670, granted Aug. 17, 1971, to J. R. Gurner et al.; 3,630,214, granted Dec. 28, 1971, to K. A. Levering; 3,719,194, granted Mar. 6, 1973, to D. M. Anderson et al.; 3,858,910, granted Jan. 7, 1975, to H. Oetiker; 4,009,729, granted Mar. 1, 1977, to A. M. Vik; 4,213,482, granted July 22, 1980, to J. T Gondek; 4,323,094, granted Apr. 6, 1982, to G. J. Paulis et al.; and 4,583,711, granted Apr. 22, 1986, to L. R. Johnson.
Anderson et al show a breakaway coupling for a helicopter or service station fuel line. The coupling includes a frangible sleeve that is connected to each of two separate confronting coupling bodies by frangible pins. The sleeve itself breaks under shear or bending forces. The pins break to allow the sleeve to disconnect from one or both of the bodies under axial, apparently tension, forces. The breaking of the sleeve or the pins allows the bodies to separate which in turn allows springs to seat valve members by moving them axially toward each other. In the assembled valve, under normal conditions, two triggers hold the valve members in their open positions. Each trigger has a longitudinal arm that abuts the valve member and a radial arm extending between confronting noses of spiders positioned in the outer ends of the bodies. Apparently, when the bodies separate, the triggers are allowed to fall away from the fuel line.
Levering discloses a fluid coupling for an aircraft fuel cell and hose or for adjacent fuel cells. In one embodiment, a central body is threadedly connected to a fuel cell fitting and a hose fitting. Bending or shear forces cause a rod holding the valve elements apart to become dislodged and thereby allow the valve elements to move toward each other and seat. Compressive forces collapse a narrow neck portion of the body resulting in fracturing of a shear pin positioned in the center of the rod to release the rod. In another embodiment, two fuel cells or tanks are connected to a bulkhead by a coupling. The coupling includes two fittings, each connected to its respective tank by a nut assembly. Radially extending shear pins connect overlapping portions of the fittings. Tensile forces shear the pins to allow the center rod to drop out as the fittings separate. Shear forces fracture the narrow neck of one of the fittings to allow the rod to drop out. Bending forces "likewise" fracture the narrow neck or the shear pins, or both, to allow the rod to drop out. In both embodiments, Levering discloses a rubber liner that stretches to seal the line to prevent leakage if the narrow neck is only partially broken.
The Sutton et al. patent, the two Neuschotz patents, and the Vogt patent each disclose a coupling for aircraft fuel cells. In each of the couplings, the valve elements are held apart by abutting members or by spring loaded plungers connected by a cable. The valves are actuated by the breaking of a frangible connecting member or by separating movement of the cells acting on a cable. The two Neuschotz patents and the Vogt patent disclose ball detents which hold the valve elements in their normal open positions.
Paulis et al disclose a breakaway valve assembly for an aircraft fuel inlet fitting. The assembly breaks apart under crash conditions to allow a fuel tank to separate from the fitting and the aircraft structure. The assembly includes a frangible sleeve with one end attached to the fuel tank by a flange and retaining ring and an opposite end threadedly connected to the fitting. An axially center portion of the sleeve has a circumferential groove formed thereon. When an axial tension load is created on the sleeve by movement of the fuel tank away from the aircraft structure, the sleeve fractures around the groove to allow the tank to freely separate. Each of the fractured ends are then sealed automatically by valve elements that are described as being "conventional".
Johnson discloses a coupler for an agricultural tractor hydraulic line. One end of the coupler is threadedly connected to a control valve or a rigid conduit on the tractor. The other end of the valve receives a nipple connected to an agricultural implement by means of a flexible hydraulic fluid line. The nipple is retained by a ball detent/sliding collar arrangement. The nipple and the valve each include a spring biased ball that seats, when the nipple and valve are separated, to close the respective joint end. Apparently, the balls hold each other in an unseated position when the nipple is connected. The coupler is described as allowing for breakaway without damage in the event of an accidental disconnect of the implement from the tractor. This is apparently accomplished by allowing an axial pull on the nipple to release the detent and pull the nipple away from the valve.
The Kopaska coupling device is also intended for use in a tractor hydraulic equipment line. The couplers disclosed by Cator, Jarnagan et al., Kopaska, Gurner et al., Vik, and Gondek each have two ends which are connected together by a ball detent/sliding sleeve arrangement. The Ulrich coupler ends are held together by a radial pin that is latched by a spring. In each of these seven patents, the two ends of the coupler are sealed by spring loaded valve elements when the coupler is disconnected. In the Ulrich and Cator couplers, ball valve members contact each other to unseat each other when the coupler is connected. In the Jarnagan et al. and Gondek couplers, a center spring holds the valve elements away from their seats. In the Kopaska and Gurner et al devices, pressure holds one valve element unseated and a plunger or piston unseats the other element. Vik discloses an intermediate cam and valve arrangement which holds the ball valves away from their seats.
Valves which close in response to remote line conditions are disclosed by U.S. Pat. Nos. 2,381,484, granted Aug. 7, 1945, to R. H. Blank; 2,537,212, granted Jan. 9, 1951, to J. A. Danielson; 2,590,918, granted Apr. 1, 1952, to W. E. Barnes; 2,962,044, granted Nov. 29, 1960, to G. W. Charboneau; 2,970,607, granted Feb. 7, 1961, to G. H. Peck et al.; 3,049,143, granted Aug. 14, 1962, to E. J. Hellems et al.; and 3,098,500, granted July 23, 1963, to T. J. Gruber. The Blank, Danielson, Peck et al., and Hellems et al. devices are designed to shut off an automobile hydraulic brake line when there is a leak or break in the line U S. Pat. No. 1,942,096, granted Jan. 2, 1934, to T. W. Hallerberg, discloses a control valve for a lubricating system which includes spring biased plungers that seat under changes of pressure.
The above-cited patents and the prior art that is discussed and/or cited therein should be studied for the purpose of putting the present invention into proper perspective relative to the prior art.